The present invention relates generally to an electrical circuit which supplies power simultaneously to a primary load and a plurality of secondary loads; and specifically to a power sensing device which automatically supplies power to the secondary loads when it senses that the primary load is on, and automatically turns off power to the secondary loads when it senses that the primary load is off.
The purpose of the present invention is to introduce a device (sensor) that will aid in the reduction of waste in different areas in which electricity is used. A potential source of waste occurs when electrical devices are inadvertently left on. The task of enhancing a user's control of electricity so that electrical power is automatically supplied or removed from electrical equipment is alleviated, to some extent, by the following U.S. Pat. Nos., which are incorporated herein by reference:
U.S. Pat. No. 3,603,817 issued to C. F. Casson on 7 Sept. 1971; PA1 U.S. Pat. No. 3,651,335 issued to T. Schimizu et al on 21 March 1972; PA1 U.S. Pat. No. 4,064,404 issued to C. B. Willmott et al on 20 Dec. 1977; and PA1 U.S. Pat. No. 4,322,632 issued to E. F. Hart et al on 30 Mar. 1982.
All of the above references are presented as samples of prior art that use a triac thyristor as a solid state sensing/switching means. The Casson reference discloses a solid state means for selective energization of parallel loads. Schimizu et al disclose an electric circuit for sequentially operating a plurality of AC loads. The Willmott et al reference discloses an accessory for a garage door opener which includes a circuit which is energized when the garage door is operated. The reference of Hart et al includes a circuit for applying power to one or more load devices under control of a remotely located, manually operable switch.
While the references cited above are instructive in the art of solid state sensing and switching devices, the need remains for a design for an automatic means which senses, whether any designated primary load is on or off, and supplies power to as plurality of second loads when the primary load is on, and removes power from the secondary loads when the primary load is off. The present invention is directed towards satisfying that need.